{ "id": "2406.06065", "version": "v1", "published": "2024-06-10T07:22:14.000Z", "updated": "2024-06-10T07:22:14.000Z", "title": "Impossibility of decoding a translation invariant measure from a single set of positive Lebesgue measure", "authors": [ "Aleksandar Bulj" ], "comment": "5 pages", "categories": [ "math.CA" ], "abstract": "Let $\\mu$ be a translation invariant measure on $(\\mathbb{R}^d,\\mathcal{B}(\\mathbb{R}^d))$ and let $\\lambda$ denote the Lebesgue measure on $\\mathbb{R}^d$. If there exists an open set $U$ such that $0<\\mu(U)=\\lambda(U)<\\infty$, it is a simple exercise to show that $\\mu=\\lambda|_{\\mathcal{B}(\\mathbb{R}^d)}$. Is the same conclusion true if $U$ is merely a Borel set? The main purpose of this short note is to construct a measure that provides a negative answer to this question. Incidentally, this construction provides a new example of a translation invariant measure with a rich domain and range that is not Hausdorff, a problem previously studied by Hirst. Although the constructed measure may exist in the literature, we were unable to locate any references to it.", "revisions": [ { "version": "v1", "updated": "2024-06-10T07:22:14.000Z" } ], "analyses": { "keywords": [ "translation invariant measure", "positive lebesgue measure", "single set", "impossibility", "open set" ], "note": { "typesetting": "TeX", "pages": 5, "language": "en", "license": "arXiv", "status": "editable" } } }